Radar-transceiver for microwave and millimetre applications

ABSTRACT

This invention concerns a transceiver module (send/receive module) for microwaves and millimeter wave applications or associated module platform concepts for interconnecting partial modules to make an overall module, which is particularly suitable for mass production. The transceiver module contains a) one or more individual electronic components, which in particular comprise active circuit components of an (preferably voltage-controlled) oscillator, a mixer and a frequency divider, and b) a substrate with a multilayer structure and integrated circuit elements, in particular a hybrid ring of the mixer and a resonant circuit of the voltage-controlled oscillator. The individual electronic components are located on the top side of the substrate. This invention makes it possible to combine the send and receive functions in a compact component with a three-dimensional integration of the high frequency components.

This invention concerns a radar transceiver (transmit/receive module)for microwave and millimeter wave applications and associated moduleplatform concepts for interconnecting sub-modules into a completemodule.

A radar transceiver is a very high frequency device for locating objectsin space or for measuring speed which can emit electromagnetic waves andcan receive and process electromagnetic waves reflected by the targetobject. A radar transceiver usually contains several interconnected veryhigh frequency modules which perform various functionalities in thefrequency range of 1 to 100 GHz.

The frequency range between 1 GHz and 30 GHz is called the microwaverange (MW range). The frequency range from 30 GHz upward is called themillimeter wave range (mmW range). The very high frequency modulesdiffer from the high frequency modules in particular in that “waveguides”, e.g., micro strip circuits and coplanar circuits, are usuallyused for very high frequency circuits beyond 5 GHz.

Transceivers or transceiver components are particularly employed in thefollowing areas of application: for automobile radar modules, forexample automobile radar at 24 GHz and 77 GHz, for keyless entrysystems, as well as generally for data communication systems, e.g., forWireless Local Data Networks WLAN, optical modules, such asmultiplexers, modulators and transmitter/receiver units, for front endmodules for broadband communication, e.g., LMDS (Local MultimediaDistribution System) and base stations of radio facilities.

In the microwave range from 1 to 18 GHz it has, until the present, beencustomary to interconnect the various circuit components (very highfrequency modules) on a soft board (printed circuit board made of amaterial with a low absorption of electromagnetic waves in the very highfrequency range) by means of SMD methods (SMD=Surface Mounted Device).However the SMD components are usually unsuitable for applications atfrequencies higher than 18 GHz.

For example, a transceiver module produced by means of this technology,which contains the following components on a 30 mm×30 mm board, isknown: a voltage-controlled oscillator made of discrete SMD elements(one transistor and two diodes) and a mixer. In addition, an antenna, afrequency divider and a frequency regulating loop are attachedexternally to this module.

Modules which can be used for the millimeter wave band are nowadaysusually produced on thin layer substrates. The thin layer substrate cansimultaneously carry one or more chip elements. The chip elements arefastened to the support substrate and electrically interconnected withit by means of wire bonding or flip-chip methods.

The disadvantage of the heretofore known transceiver modules is thatthey require a large amount of space and, for this reason, they often donot satisfy the application-orientated requirements (e.g., inradio-linked key applications for automobile remote keyless entry, RKE).

It is the object of the present invention to disclose a novel, highlyintegrated design of a radar transceiver in a compact module.

This objective is achieved according to this invention by means of anelement having the characteristics of claim 1. Advantageous embodimentsof this invention are provided by the further claims.

This invention discloses a radar transceiver, containing:

-   -   at least one oscillator, which comprises at least one active        circuit element, at least one frequency determining oscillator        circuit and at least one component that is applicable for        purposes of frequency detuning,    -   at least one mixer, which comprises at least one diode and at        least one passive circuit element,    -   a substrate with at least two dielectric layers located directly        on top of each other, in which metallized surfaces are placed on        top of, below and between the dielectric layers, such that the        lower surface of the substrate has external contacts for        connecting it to a system support and the top side of the        substrate has contacts for connecting it to the external        electrodes of the at least single individual electronic        component,    -   one or more individual electronic components located on the top        side of the substrate, which comprise    -   at least one active or nonlinear circuit component of the mixer        and    -   at least one active or nonlinear circuit component of the        voltage-controlled oscillator,        where the at least single passive circuit element of the mixer        and/or the at least single resonant circuit of the        voltage-controlled oscillator is integrated in one of the        metallized surfaces of the substrate.

The at least single passive circuit element of the mixer and/or the atleast single resonant circuit of the voltage-controlled oscillator arepreferably at least partly integrated in the internal metallizedsurfaces of the substrate. Said elements can also be at least partlydistributed over several internal metallized surfaces instead of in onlyone internal metallized surface. In an advantageous variant, the passivecircuit element of the mixer and/or the resonant circuit of theoscillator are located entirely in the interior of the substrate.

At least one internal metallized surface is thus structured so that atleast one passive circuit element of the radar transceiver circuit isbuilt up on this surface, in addition to shielding metal (ground plane)surfaces or the circuit terminations of a connecting circuit, which mayalso be located in this plane.

The connection between the metallized surfaces preferably occurs bymeans of plated pass-through holes. It is also possible to make theconnection through capacitive or inductive field coupling of two metalstructures located on different metallized surfaces.

Said oscillator is preferably a voltage-controlled oscillator.

The oscillator generates electromagnetic oscillations in the radartransceiver at the given very high frequency—a reference signal, whichis directed over the transmission path at an external transmittingantenna or an antenna integrated in the substrate of the radartransceiver and is emitted from there toward a target object as thetransmitted signal. The signal reflected by the target object arrives atthe mixer via the receiving antenna and the reception path of the radartransceiver and the mixer mixes the transmitted and received signalswith each other and supplies a demodulated signal. The demodulatedsignal is passed to an ASIC (Application Specific Integrated Circuit),which contains a frequency control loop, preferably a phase locked loop(PLL) and outputs a control voltage for purposes of frequency control ofthe (voltage-controlled) oscillator. The oscillator usually contains atleast one nonlinear (or active) circuit element for purposes offrequency detuning, e.g., a varactor diode. The frequency control loopis, e.g., a digital or analog PLL or an analog frequency control strip.

The ASIC is expediently connected externally. It is possible for theASIC to be attached to the top side of the substrate as an individualcomponent.

These or other individual electronic components that are present have atleast two external electrodes located on the bottom surface, whichelectrodes are electrically connected with the contacts on the top sideof the substrate.

An individual electronic component is above all a nonlinear or an activeelectronic element, in particular a chip element.

A nonlinear or active individual component is understood to be adiscrete nonlinear or active circuit element such as a diode or atransistor, or a chip element with or without a housing comprising atleast one nonlinear or active component. The nonlinear or activeindividual component can, in addition, comprise one or more passivecircuit elements (selected from among an inductance, a capacitance, aresistance, a circuit termination).

The active individual component that is constructed as a chip elementcan be a microwave chip, a millimeter wave chip or an IC element(IC=Integrated Circuit). The IC element can in turn be an MMIC element(MMIC=Monolithic Microwave Integrated Circuit).

The active individual components can, for example, be constructed usingSi, SiGe, GaAs or InP semiconductor technology.

Aside from one or more nonlinear or active individual components, theradar transceiver module of this invention can also contain one or morepassive individual components.

A passive individual component is a discrete element selected from amonga capacitor, a coil, a resistor or a chip element which comprises atleast a part of the following circuits: an RLC circuit, a filter, aswitch, a directional coupler, a bias network, an antenna, an impedancebuffer or an adaptive network.

The individual electronic component has at least two external contactsfor establishing an electrical connection with the metallic structuresembedded in the substrate.

In the very high frequency range relevant to this invention, the atleast single individual electronic component is preferably connectedmechanically or electrically to the substrate and to the integratedcircuit elements by means of the flip chip method, so that itsstructured side faces the top side of the substrate.

Aside from the at least single (nonlinear, passive or active) individualelectronic component, one or more discrete electronic elements (e.g., acoil, a capacitor or a resistor) as well as one or more supportingsubstrates with passive HF structures such as filters or mixers, inparticular supporting substrates structured with thin layer technology,can be located on the top side of the substrate.

Substrates are here understood to be all kinds of planar circuitsupports. These include ceramic substrates (thin layer ceramics,thick-film ceramics, LTCC—Low Temperature Cofired Ceramics, HTCC—HighTemperature Cofired Ceramics, LTCC and HTCC are multilayer ceramiccircuits), polymeric substrates (conventional printed circuit boards,such as FR4, so called soft substrates whose polymer base e.g., consistsof PTFE=Teflon or polyolefins and which are typically glass fiberreinforced or filled with ceramic powders), silicon as well as metallicsubstrates in which metallic printed circuits and a metallic base plateare insulated from each other by means of polymers or ceramic materials.Substrates are here understood to also include so called MoldedInterconnection Devices (MID), which consist of thermoplastic polymerson which printed circuits are formed. A substrate in the sense of thisinvention is preferably of the monolithic design, where, in the case ofa ceramic substrate, all dielectric and metal layers are produced in asingle process or are sintered together.

The substrate contains integrated circuit elements, above all passivecircuit elements of the mixer (in particular a hybrid loop), theoscillator (in particular a resonant circuit) and the structures of oneor more low-pass filters. An integrated circuit element is in particularunderstood to be an inductance, a capacitance or a line, e.g., atransmission line emitter, a connecting line, or a line termination.These can, in a known manner, be present as printed circuits in between,within and on top of the dielectric layers of a substrate having amultilayer structure and they thus constitute integrated circuitelements. Vertical connections between the printed circuits in differentlayers (plated-through holes) also count as integrated circuit elements,since on the one hand they serve the purpose of vertical signaltransmission and on the other hand, in particular in the very highfrequency range, they represent both a (parasitic) inductance and a(parasitic) capacitance. Several individual integrated circuit elementstogether form integrated circuits, in particular passive circuits suchas a filter or (at least a part of) a mixer. Integrated circuit elementscan furthermore constitute at least a part of at least one activecircuit which is electrically connected with the active individualcomponents on the surface of the substrate.

In the case of very high frequencies, particularly in the mmW range,capacitances and inductances are often present as distributed elementsconstituted by line terminations. The capacitances can, for example, beconfigured as radial stubs.

The bottom surface of the substrate has external contacts forestablishing an electrical connection with, for example, the printedcircuit board of a terminal device.

Metallized surfaces are particularly located between the dielectricsubstrate layers. The top side of the substrate and the bottom surfaceof the substrate are here also considered to be metallized surfaces.

The top side of the substrate carries conductive structures(metallizations) which are suitable for producing an electricalconnection between the metallized surface within the substrate and theat least single individual electronic component on the top side of thesubstrate.

The total thickness of the dielectric substrate layers is typicallybetween 0.3 and 1.5 mm.

In comparison with known radar transceiver modules, the radartransceiver module of this invention is characterized by athree-dimensional integration of the circuit elements (in particularthose of the mixer and the oscillator) within the substrate and it isthus particularly space-saving (small base surface area).

In the following, this invention is described in greater detail based onexemplary embodiments and the associated schematics and therefore withfigures that are not true to scale.

FIGS. 1 a and 1 b respectively show a block diagram of an exemplaryradar transceiver circuit

FIG. 2 shows a radar transceiver module of this invention as a schematiccross section

FIG. 3 shows a perspective representation of the three-dimensionalintegration of the very high frequency circuit elements into themetallized surfaces of the substrate

FIG. 4 shows an advantageous embodiment of the radar transceiver moduleof this invention as a schematic cross section

FIG. 1 a represents a block diagram of a radar transceiver circuit.

The radar transceiver module of this invention in FIG. 1 a contains avoltage-controlled oscillator VCO, whose frequency is tunable with acontrol voltage Vtune, a mixer MIX and a customized integrated circuitASIC with a frequency control loop, e.g., a phase-locked loop PLL (in afurther embodiment, the frequency controlled or phase-locked loop can,for example, be integrated in a frequency divider).

The radar transceiver module of this invention shown in FIG. 1 aadditionally contains a frequency divider FD, which divides thefrequency of the output signal of the voltage-controlled oscillator VCOdownward and outputs a signal ZFout for controlling the phase-lockedloop of the ASIC.

The oscillator, in particular the voltage-controlled oscillator, thefrequency divider and the phase-locked loop integrated in the frequencydivider or located externally in the ASIC together constitute afrequency control loop.

Alternatively, as in the advantageous embodiment represented in FIG. 1a, the radar transceiver module of this invention can, respectively,contain an amplifier TX-AMP or RX-AMP in the transmission or thereception path. These can be available as individual components that areseparated according to their function or they can be located in one ormore individual components along with other circuit elements, e.g., thecircuit elements of the mixer, the (volt-age-controlled) oscillator orthe frequency divider.

That output signal HFout is transmitted by means of the transmittingantenna TX-ANT. The reflected signal is received by the receivingantenna RX-ANT. Both the transmitting antenna and the receiving antennacan be constituted of the metallized surfaces of the substrate(including the bottom surface of the substrate). A further possibilityis that the transmitting and/or the receiving antenna are connectedexternally via very high frequency terminals.

The mixer MIX mixes the received signal with the signal of theoscillator VCO and outputs a demodulated signal MIXout, which carriesthe desired information (e.g., about the distance or the speed of thetarget object) and which can be further processed externally to, forexample, provide a visual representation.

Said radar transceiver circuits (in particular the active circuitelements) are fed a supply voltage Vcc and/or a current Icc.

The transceiver is simultaneously also applicable for short distancedata transmission, e.g., for application as a radio activated key.

Amplitude shift keying ASK or frequency shift keying FSK are applicablee.g., for purposes of simple close distance data communication.Amplitude shift keying is achieved by switching the signal source (theoscillator or the transmission amplifier, if available) on and off atthe clock rate of the data bits. Frequency shift keying is achieved byclocking a frequency regulating loop.

In another embodiment of the radar transceiver shown in FIG. 1 b, theantenna TRX-ANT simultaneously serves the purpose of radiating theemitted signal receiving the [reflected] signal.

In the radar transceiver module of this invention, all relevantfunctionalities of a radar transceiver (frequency control of theoscillator, signal amplification, signal emission, signal reception,demodulation) are integrated in a compact module, with the integrationof the passive circuit elements taking place in a three-dimensionalmanner within the metallized surfaces of the substrate; see FIG. 2.

FIG. 2 describes the general properties of the three-dimensionalstructure of a radar transceiver of this invention by means of aschematic cross section.

FIG. 2 shows the schematic cross section of a radar transceiver of thisinvention with an individual electronic component CB and a multilayersubstrate SU. The individual electronic component CB with outerelectrodes AE is, in this case, a chip element, which comprises at leastone nonlinear or active circuit element of a mixer and/or of a(voltage-controlled) oscillator (in particular a diode or a transistor).The individual electronic component CB can furthermore contain one ormore passive circuit elements (selected from among a capacitor, aninductance or a resistor). The individual electronic component CB isconnected electrically by means of bumps BU with various metallizedsurfaces, which in particular comprise conductive structures LS on thetop side of the substrate and further structures LS1 embedded in themultilayer substrate SU. The conductive structures LS and LS1 constituteintegrated circuit elements IE. The electrical connection is, forexample, made by means of flip chip technology or SMD (SMD=SurfaceMounted Device) technology. The substrate SU has conductive structuresfor purposes of producing said electrical contact with the top side aswell as external contacts AK to the bottom surface for purposes ofproducing an electrical connection with the printed circuit board of aterminal device. The external contacts AK can be configured as Land GridArrays (LGA) or it can be additionally provided with solder spheres(μBGA, or Ball Grid Array). Compared with the LGAs, μBGAs have theadvantage of higher thermomechanical strength, which is essential forproduct qualification for automotive applications.

It is additionally possible to use needle-shaped external contacts(leads) and non-galvanic transitions between the structural element andthe printed circuit which is to be attached externally, e.g., wave guidetransitions or slot couplings (in particular field coupling of the veryhigh frequency signals from the transceiver module to the externallylocated antenna or to the system support via slot structures located onthe bottom surface of the module). The vertical signal transfer withinthe substrate SU takes place by means of plated-through holes DK1 andDK2.

It is possible that the external electrodes of the individual electroniccomponent are needle-shaped (leads).

The individual components above all comprise nonlinear or active circuitelements of the mixer and the (voltage-controlled) oscillator, whiche.g., cannot be integrated in the substrate. It is possible for thecircuit elements of the mixer and the oscillator to be (at leastpartially) configured in a shared individual component or in differentindividual components.

In an advantageous embodiment of this invention, it is possible for asingle individual component (at least partially) to contain the circuitelements of the mixer, the oscillator and of a frequency divider. It isalso possible for the circuit elements of the mixer, the oscillator andthe frequency divider to be (at least partially) contained in threedifferent individual components. It is furthermore possible for thecircuit elements of the mixer and the voltage-controlled oscillator tobe (at least partially) located in a shared individual component and forthe circuit elements of the frequency divider to be (at least partially)located in a separate individual component. Further possibilities derivefrom the following combinations: a) the circuit of elements of the mixerand the frequency divider (at least partially) in a shared individualcomponent and the circuit elements of the oscillator (at leastpartially) in a separate individual component, b) the circuit elementsof the oscillator and the frequency divider (at least partially) in ashared individual component and the circuit elements of the mixer (atleast partially) in a separate individual component.

In an advantageous embodiment, the radar transceiver module of thisinvention contains the following single components on the top side ofthe substrates: an IC, which (at least partially) comprises the(voltage-controlled) oscillator and the frequency divider, as well asone or more (e.g., two or four) discrete diode chips, which accomplishthe mixer function; see also FIG. 4.

In place of an integrated circuit, the oscillator can also be (at leastpartially) composed of discrete transistors, e.g., one or moretransistor chips. The mixer can be (at least partially) present as anintegrated circuit. The circuits of the mixer, the oscillator and thefrequency divider can generally be present as single chip, two chip orthree chip solutions. The resonant circuit of the (at least single)oscillator can be partly or entirely implemented on one chip (i.e., inan individual electronic component).

In the advantageous exemplary embodiment of this invention shown in FIG.2, the at least single individual electronic component CB is covered bya film SF to protect it against humidity and external mechanical effects(cover film).

The film covering represents a film, whose shape is (or becomes) fittedto that of the components which are to be protected (or which are to becovered). The film covering thus extends over the back of the activeindividual component and seals against all sides of the surface of thesubstrate so that the active individual component is completely coveredand thus protected against external mechanical effects, dust andhumidity.

The covering of the individual components with the film is also calledlaminating. In being laminated the film is permanently deformed. Thefilm covering preferably consists of a polymer which has particularlylow water absorption, e.g., polyimide, fluorine-based polymers such aspolytetrafluoroethylene (PTFE) or polyolefins such as (cross-linked)polypropylene or polyethylene. The film covering can in addition consistof a metal and it can be particle-filled or fiber-filled. The filmcovering can furthermore be or become coated with a metal or withceramic.

It is possible for the film covering to cover all individual componentson the top side of the element completely and jointly.

For purposes of shielding against the environment, the film covering canadditionally be covered with a metal layer. This layer can, for examplebe deposited by sputtering, galvanizing, chemical metal separation,vaporization or by a combination of the aforesaid methods. For purposesof mechanical stabilization, the individual components located on thetop side of the substrate are, in this exemplary embodiment, coveredwith a casting resin GT. It is alternatively possible to omit thecasting resin. Casting resins are, in this case, understood to be anymaterials that are applied to the film in the liquid state and aresolidified by curing (chemical reaction) or cooling. These include bothfilled and unfilled polymers, such as masking compounds, Glob Topcompounds, thermoplastics or plastic adhesives, as well as metals orceramic materials, such as ceramic adhesives. Glob Top is a castingcompound, which, because of its high viscosity, flows only slightly andtherefore encloses the individual components which are to be protectedas a droplet-shaped mass.

In an advantageous embodiment of this invention, the metallized film canbe covered with a casting resin after it is laminated. In anotherembodiment, It is possible to apply the metal layer onto the sealingcompound rather than onto the cover film.

In an advantageous embodiment of the element of this invention with aceramic substrate, the film is partially removed at the edges adjoiningthe substrate—for example, by means of lasers—and is only thereaftercoated with metal so that the individual components that are to becovered are completely enclosed by metal or ceramic and are thushermetically sealed.

It is possible for the radar transceiver module of this invention toreceive an (additional) cover for the purpose of mechanical protectionof the individual electronic components located on the top side of thesubstrate.

The bumps BU serve the purpose of producing an electrical connectionbetween the integrated circuit elements IE embedded in the substrate SUand the at least single individual electronic component CB and possiblythe further individual components located on the top side of thesubstrate. The bumps usually consist of solder, for example SnPb, SnAu,SnAg, SnCu, SnPbAg, SnAgCu at different concentrations, or of gold. Ifthe bump is made of solder, the element is connected to the substrate bysoldering; if it is made of gold, then the individual components CB andthe substrate SU can be interconnected by thermocompression bonding,ultrasonic bonding or thermosonic bonding (sintering or ultrasonicwelding methods). For very high frequency applications, the height ofthe flip chip bumps must be sufficiently low to allow only a smallamount of electromagnetic radiation to emerge from the individual veryhigh frequency component and to be absorbed by the laminated film. Onepossibility for achieving the low height of the flip chip bumps is inparticular offered by thermocompression bonding.

In a further embodiment of this invention, the individual electroniccomponents can be SMD components.

Aside from active individual components, it is also possible to attachpassive individual components, in particular discrete coils, capacitors,resistors or individual chips with passive circuits (for examplefilters, mixers, interface circuits) to the top side of the substrate.It is possible to compensate for the detuning of the element by thehousing with additional discrete passive compensation structures.

The individual electronic components as well as the integrated circuitcomponents can form at least a part of the following circuits: a highfrequency switch, an interface circuit, a high-pass filter, a low-passfilter, a band pass filter, a notch rejection circuit, a poweramplifier, a coupler, a resetting coupler, a bias circuit or a mixer.

If the at least single individual electronic component does not containsignal conducting structures on its surface that are to be protected(for example, if all circuit elements and circuits are embedded withinthe multilayer substrate), it is possible to first cover this individualcomponent with the casting resin and to apply a cover film only afterthe resin is cured.

The signal lines in the element of this invention can either becompletely enclosed within the substrate or at least a part of thesignal lines can be located on the top side of the substrate.

It is possible for either at least a part of the signal lines as well asDC connecting lines to be located on the top side or the bottom surfaceof the substrate, or for all signal lines to be enclosed within thesubstrate.

The very high frequency connecting lines in the radar transceiver moduleof this invention can be configured as microstrip lines or as “suspendedmicrostrip” lines (microstrip lines covered with a dielectric), two-wirelines or coplanar lines (three-wire lines) or triplate lines (coplanarlines covered with a dielectric).

The vertical, very high frequency signal pass-throughs can be configuredas two or three parallel plated-through holes (with two or three wirelines) or as a kind of coax line. In the latter case, the signalconducting plated-through hole is surrounded by several plated-throughholes arranged all around it and connected to ground in the manner of acoaxial connection.

FIG. 3 shows an exemplary integration of the very high frequency circuitelements (in this case a mixer) into the metallized surfaces of thesubstrate in a perspective view. Two very high frequency connectinglines VL and two low-pass filters TPFI or the hybrid ring HR are locatedin the upper and/or in the bottom metallized surfaces. Each low-passfilter is constructed of radial stubs RS and thin conductor lines DL.The thin lines then act inductively, and the radial stubs actcapacitively. The radius of the radial stubs as well as the length ofthe thin lines between two radial stubs amount to (approximately) onequarter of the wavelength, so that a short-circuit for very highfrequency signals captured at the wide end of the radial stubs occurs atthe point of attachment of the radial stubs. The hybrid ring is attachedvia plated-through holes DK2, e.g., to the mixer diodes located on thetop side of substrate or to the mixer IC.

FIG. 4 shows an advantageous embodiment of the radar transceiver of thisinvention with a (voltage-controlled) oscillator OSZ-IC and two mixerdiodes MIX1 and MIX2 as a schematic cross section. The reference symbolsin this figure correspond to those in the figures described above. Theembedded circuit elements (e.g., the hybrid ring HR, the oscillatorresonant circuit RES and the low-pass structures TPFI) are surrounded byground plane surfaces GND1, GND2 and GND3. The structure ANT is eitheran antenna structure or alternatively a very high frequency connector toan external antenna.

The substrate contains dielectric layers with differing dielectricconstants or different layer thicknesses. In this exemplary embodiment,the dielectric layers, which contain the hybrid ring and the oscillatorresonant circuit, are thicker than the layers containing the low-passstructures. The smaller the distance between a metallized surface withthe signal carrying structures and a metallized surface with the groundplane and the higher the dielectric constant of the correspondingdielectric layers, the higher is the capacitance (low impedance in thesense of the very high frequency) of the conductor structures located inthe first of the aforesaid metallized surfaces.

In this exemplary embodiment, the inside of the substrate is dividedinto two functional sections—an oscillator section located on the leftof the figure and a mixer section located on the right of the figure—towhich the external contacts Zfout, Vtune, Vcc and/or MIXout forinputting and outputting the low-frequency signals on the bottom surfacecorrespond.

The mixer section contains a hybrid ring (ratrace or 90° hybrid ring)HR, low-pass structures TPFI, two Schottky diodes MIX1 and MIX2 and thecorresponding vertical connections via the plated-through holes. Theoscillator section contains an IC, which partially contains the(preferably voltage-controlled) oscillator and a frequency divider (anOSZ-IC), a resonant circuit RES embedded in the substrate, low-passstructures as well as connecting lines and plated-through holes.

The radar transceiver module of this invention represents a componentwhich can be readily processed with conventional standard SMD mountingprocesses. The radar transceiver module of this invention can inparticular be mounted on a system circuit board, e.g., an FR4 printedcircuit board or a soft board usually made of laminates.

In the case of particularly complex system topologies, which cannot beachieved in a fully integrated module, it is, according to thisinvention, possible to achieve the appropriate subfunctions of the radartransceiver in partial modules which are interconnected on a systemcircuit board. One can, for example, construct the radar transceiverwith two separate modules—a partial transmitter module, which containthe oscillator section, and a partial receiver module, which containsthe mixers section. In some cases, if an antenna, e.g., a directionalantenna, takes up much of the substrate surface, it is expedient toimplement such an antenna outside of the substrate or the module whichis described here. Suitable system supports for producing the connectionbetween the partial modules and, for example, for implementing theplanar antenna are in particular ceramics and laminates based on Teflonor glass fibers.

For the sake of clarity, this invention had been described based only ona few exemplary embodiments, but it is not limited to these. Furtherpossible variations arise from other relative configurations of circuitelements, individual components, the cover film layer, the casting resinand the metal layer, which differ from the embodiments that arerepresented.

Further possible variation options arise from further relativeconfigurations of the oscillator, the mixer, the frequency divider, thelow-pass filter, the amplifier or the antennas in the transmission orreception path, which differ from the represented embodiments.

Further possible variations arise with respect to the number of the(aforementioned) circuits that are used and regarding the method forconnecting the individual component to the substrate as well as thesubstrate to an external printed circuit board.

1. A radar transceiver, comprising: an oscillator, comprising an activecircuit component, a resonant circuits and a circuit component forfrequency tuning, a mixer comprising a diode and a passive circuitcomponent, and a substrate comprising multiple layers, the multiplelayers comprising at least two dielectric layers stacked, the substratehaving a metallized top surface, a metallized bottom surface, andmetallized internal surfaces located between the dielectric layers,wherein an electronic component on the metallized top surface of thesubstrate comprises at least one active or nonlinear circuit componentof the mixer and at least one active or nonlinear circuit component ofthe oscillator, and wherein the passive circuit component of the mixeror the resonant circuit of the oscillator is integrated in one or moremetallized surfaces of the substrate.
 2. The radar transceiver of claim1, wherein the oscillator comprises a voltage-controlled oscillator(VCO).
 3. The radar transceiver of claim 1, wherein the circuitcomponent for frequency tuning comprises a nonlinear circuit component.4. The radar transceiver of claim 1, wherein the circuit component forfrequency tuning comprises a varactor diode.
 5. The radar transceiver ofclaim 1, wherein the mixer comprises a hybrid ring that is integrated inthe substrate.
 6. The radar transceiver of claim 1, further comprising afrequency divider for dividing a frequency of an output signal of theoscillator.
 7. The radar transceiver of claim 6, wherein the frequencydivider comprises a phase-locked loop.
 8. The radar transceiver of claim1, wherein the metallized bottom surface of the substrate comprises aterminal for connection for connecting to an external antenna.
 9. Theradar transceiver of claim 1, further comprising a part of at least oneantenna that is on the top metallized surface of the substrate or thebottom metallized surface of the substrate.
 10. The radar transceiver ofclaim 1, further comprising a cover film for covering the electroniccomponent at least partly
 11. The radar transceiver of claim 10, furthercomprising a metal layer that at least partly covers the cover film. 12.The radar transceiver of claim 10, further comprising a casting resinthat at least partly encases the cover film.
 13. The radar transceiverof claim 1, wherein at least one circuit element selected from among aninductance, a capacitance, a line or line termination is integrated inthe substrate.
 14. The radar transceiver of claim 1, wherein theelectronic component comprises a microwave chip, a millimeter wave chipor an integrated circuit element.
 15. The radar transceiver according toclaim 14, wherein the integrated circuit element comprises a monolithicmicrowave integrated circuit element.
 16. The radar transceiver of claim1, wherein the electronic component is mechanically and electricallyconnected to the substrate via flip chip technology or surface mounteddevice technology.
 17. The radar transceiver of claim 1, furthercomprising one or more electronic components selected from among thefollowing components: a discrete passive circuit element including acoil, a capacitor and a resistor, or which presents a compact circuitblock, which contains at least one individual electronic componentselected from among a coil, a capacitor or a resistor, including anycombination of individual components.
 18. The radar transceiver of claim1, wherein the substrate comprises at least two layers of lowtemperature cofired ceramic, or high temperature cofired ceramic. 19.The radar transceiver of claim 1, further comprising: a mixer diode or achip element that performs, a mixer function; and a integrated circuitelement that comprises at least a part of the oscillator and a frequencydivider.
 20. The radar transceiver of claim 1, wherein at least a partof the oscillator, a frequency divider, and the mixer is provided inone, two or three integrated circuit elements.
 21. The radar transceiverof claim 1, wherein frequency modulation occurs via frequency keying ofthe oscillator, an amplifier associated with the radar transceiver, or avery high frequency switch associated with the radar transceiver. 22.The radar transceiver of claim 1, wherein amplitude modulation occursvia amplitude keying of the oscillator, an amplifier associated with theradar transceiver, or a very high frequency switch associated with theradar transceiver.
 23. The radar transceiver of claim 1, furthercomprising an integrated circuit element comprising an amplifier that isin a transmission or reception path of the radar transceiver.
 24. Theradar transceiver of claim 1, wherein the radar transceiver comprises alow temperature cofired ceramic module or as partial modules that areelectrically connected with each other, where said partial modules areinstalled by machine using surface mounted device technology.
 25. Theradar transceiver of claim 1, wherein the substrate comprises is as amonolithic ceramic object.
 26. The radar transceiver of claim 1, whereinthe passive circuit component of the mixer, the resonant circuit of theoscillator, or both, are at least partially integrated in at least oneinternal metallized surface of the substrate.